Ambroxol, a substituted benzylamine, is an active metabolite of bromhexine, which is itself a synthetic derivative of vasicine, the active principle extracted from the plant species Adhatoda vasica. Ambroxol is an expectorant exerting mucokinetic properties, mucociliary activity, stimulation of surfactant production, anti-inflammatory and antioxidative actions and the local anaesthetic effect. Ambroxol was discovered at and has been manufactured by Dr. Karl Thomae GmbH, a division of Boehringer Ingelheim. The ambroxol patent is expired and the drug is available as a generic product from many different companies. Ambroxol was originally developed by Boehringer Ingelheim as a OTC therapy for respiratory disorders related to excessive mucus. Ambroxol's indication is secretolytic therapy in acute and chronic bronchopulmonary diseases associated with abnormal mucus secretion and impaired mucus transport. Boehringer Ingelheim markets the product under various brand names such as Mucosolvan® and Lasolvan®. Ambroxol was identified and found to be a pH-dependent, mixed-type inhibitor of glucocerebrosidase (GCase). Its inhibitory activity was maximal at neutral pH, found in the endoplasmic reticulum, and undetectable at the acidic pH of lysosomes. The pH dependence of Ambroxol to bind and stabilize the enzyme was confirmed. Ambroxol increases both the lysosomal fraction and the enzymatic activity of several mutant GCase variants. This profile of Ambroxol would allow to bind and stabilize GCase in the endoplasmic reticulum (thus preventing its degradation within endoplasmic reticulum), but without affecting GCase in the lysosomes (thus allowing it to degrade glucosylceramide). Indeed, studies showed that Ambroxol treatment significantly increased N370S and F213I mutant GCase activity and protein levels in fibroblasts originally obtained from Gaucher patients. Gaucher's disease is caused by the deficiency of glucocerebrosidase; ambroxol is a chaperone that acts by binding to and stabilising glucocerebrosidase. Zywie (formerly ExSAR Corporation) and Belrose Pharma are developing ambroxol hydrochloride (BEL 0218) for the treatment of type III Gaucher's disease. .